Quantitative determination of naphthalene in illuminating gas



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WALTER n'. FULWEILR, or WALLINGFORD, PENNSYLVANIA, AssreNoR ro THE U. G. I. CONTRACTINGCOMPANY, or PHILADELPHIA, PENNSYLVANIA, A ooRPoRa i TION OF DELAWARE.

QUANTITATIVE :DETERMINATION N APHTHALENE IN ILLUMINATING GAS.

riginal application led January 12, 1922, Serial No. 528,861. Divided and this application filed .Tune 29, 1922. Serial No. 571,717.

rlhis application is a division of my ape plication, Serial No. 528,861, tiled January 12th, 1922, which has matured into Patent 1,443,330, issued J an. 23, 1923.

The principal objects of the present application are to provide for the rapid and accurate quantitative determination of naphthalene in illuminating gas even by unskilled persons, to provide a simple, expeditious and reliable method for that purpose, and toprovide portable, compact, and comparativelyinexpensive apparatus by means of which the method can be practiced.

In the practice of the linvent-ion the naphthalene content of the gas is convertedinto naphthalene picrate by passing a known quantity of gas through a standard solution of picric acid thereby increasing the electric resistance of the solution, and the value of the electric resistances of the treated A"and of Vthe standard solutions are compared-thereby.'

estimating quantitatively the naphthalene content ofthe gas.

The invention comprises the improvements to be presently described and finally claimed andthe description will be made in connection with the accompanying draw-,ings forming part hereof and in which- Figure 1 is a top or plan view of conductivity bridge apparatus with the. cover removed and parts omitted and which embodies features of the invention.

Fig. 2 is an elevational view o'f the right- 'hand end part of the apparatus shown at the bottom of Figure 1 with parts omitted.

Fig. 3 is a transverse sectional view taken through the lower portion of Figure 1.

F igd is a view diagrammatically showing a train .of gas washing bottles and also indicating a meter.

Fig. 5 isa diagrammatic view illustrating the circuit connections ot the apparatus shown in Figure 1.

Fig. 6 is a. chart for showing the naph thalene concentration from readings taken by the apparatus of Figure 1, and

Fig. 7 is a view of a chart for another use in connection with readings taken from the apparatus shown in Figure 1.

, ln the drawings, more particularly Fig. 5,. there is shown an electric balance having two'ot its arms,.1 and 2, provided with con duetivity cells 3 and 4 and having its bridge 5 provided with a balance indicator indicated generally at 6, and with a balance adjuster` generally indicated at 7. 8 and 9v are the leads of an alternating current circuit provided with a switch 10 for making and breaking it. 1l is a step-down transformer shown as an auto transformer interposed in the alternating `current circuit and across which the electric balance is connected as by conductors 12 and 13. 14 is an inductive resistance in series with the step-down transformer 11 and with the field winding 15 and 65 serving to limit the current passing through the apparatus. The lield winding 15 appertains to the balance indicator 6 which is shown as an alternating current galvanometer having/lifted poles 16 and a xed core 70 17 and a movable coil 18 which carries the pointer 19, Fig. 1. The balance adjuster 7 is shown as a key 20 co-operating with a scale 21, Fig. 1, and adapted to be connected with points of different potential in the coil 22, and the coil 22 and the coil 23 are of equal resistance when the adjuster is in zero position. The arms 24 and`25 are of equal resistance. The conductivity cells have the same constants and are alike so that a des'cription of one. will suflice. 26 and 27 are the electrodes and they are sealed through the wall of the cell and each cell is provided with a rod 28,'arranged between one of its ends and the electrode 26, and by pushing the rod 2S in and pulling it out the 'constant of the cell can be adjusted. rlhefconstant of cell signifies thc characteristics for thepurpose intended of the ccll itself without regard to the particular iiuid employed in it.

The volumetric capacity of the cell is a factor in changing 'the constant. 29 1s a thermometer for showing the temperature of the contents of the cell. YThe tunnel 30 and tube 31 constitute an inlet tor the cell, and 95 the tube 32 constitutesnanyoverflow for the cell, thus the liquid is introduced from the bottom of the' cell in 'excess and air bubbles are avoided. 33 is a pinchv connection by which the cell can be emptied. 34 is a knowh 1m resistance that may be connected by binding posts 35 across the conductivity cell 4 for a purpose to be presently described. The described parts are assembled in a cabinet. 36

can En in such a Way that some of them are exposed as shown in Figures 1 and When the lid oi the cabinet is open or removed, and others ot the parts are concealed Within the cabinet. 37 is a socket for the reception of a line plug. The bracket 38 may be turned about the pivot 89 and it serves tosupport the tunnels 30. rlhe apertures 40 serve for the reception of the connections 31 and 82. 1ihe Washing` bottles 4l, 42 and 43 of the train ot' Washing' bottles shown in Fig. 4 and which includes a meter, indicated at 45, are filled with a standard solution of picric acid. 'lhe washing bottles 46 and 47 contain reagents and when present they serve to remove certain ingredients other than naphthalene from the gas.

ln making` a test gas is passed through the train of Washingbottles at an appropriate rate, for example, a rate not exceeding .8 cubic feet per hour until a distinct precipitate appears in bottle 41. The flow of gas is then stopped and the appropriate meter readings made. The train is then disconnected and the contents of bottles 46 and 47 discarded. Bottles 41, 42 and 43 are then brought to approximately O C., for example, from 27 to 23C C., and are allowed to remain at that temperature for ay evtfn moments V4and then they are vigorously shaken. Bottle 41 contains the insoluble naphthalens picrate and the bottle 42 is a catch bottle for insoluble picrate. rlhe bottle 43 contains standard picrie acid solution as it may have been modied by the passage of' gas through it. The electrical resistances ot the standard solution and of the contents of the bottle 41, and perhaps theY bottle 42, are not the same, the standard solution being of greater conductivity. lfilter papers are put into the tunnels and th'econtents of bottle 41 is filtered into, i'or example, the righthand conductivity cell 4 and the contents oi'Y bottle 4?) is 'filtered into the lefthand conductivity cell 3. ln both cases the additions are continued until the solution begins to overilow from the upper tubes 32. rihe temperature of the thermometers 29 is then read and the solutions are brought, for example, by Warming one or the other of them with the hand, to approximately the same temperature, for example, within .10 C. of each other. rlhe absolute temperature is not so important as the relative temperature. The circuit is then. crnnpleted, for example, by pressing the push button 10. and the balance adjuster T` is turned until the balance indicator 6 stands at zero. The push button can then be released and the readingof the dial 21 and of the thermometers 29` observed. rThe result of this isthatfthe value of the electric resistances oi the standard and of the other solu tion are comparedand the relative difference noted on the dial 21. The `scale readremain.

ing at 21 is noted along the horizontal line of the chart shown in Fig. 6 and is -carried up to the calibrated temperature lines on the chart as indicated, for example, at a,

and at the intersection of the line a with the observed temperature line and at the lett as indicated by the line c, will be found as at e the grains of naphthalcne per hundred cubic feet of gas when one cubic foot has been used as a sample. ln most cases it is unnecessary to measure the resistance of the contents of bottle 42. However, some naphthalene may have reached bottle 42 and in such case a small amount of the solution in bottle 42 is filtered in and used to Wash out the cell 4, and the cell is then filled with the solution from bottle 42 and the di'erence in resistance determined as before. lin case both bottles 41 and 42 are read on the dial 21 the curve is entcxid with the sum ot the dial readings.

The standard pieric acid solution may Well be approximately a saturated solution at 25o C. Such a solution ismade up and poured into the cell 3 which can be Well Washed out with it. rEhe fixed resistance 34 is then connected to the binding post 35 and a reading made on the dial 21. The calibrated curve for the standard picric acid solution shown in Fig. 7 is then referred to b v applying the temperature reading at the left as indicated at and if the reading or" i/ at the bottom ot the chart does not agree With the reading' on the scale 21, the proportions are changed until these readings agree.

n the description and claims reference is made to naphthalene, but the invention is applicable to the determination of ammonia and hydrogen sulphide by using appropriate solutions, for example. for ammonia. use can be made oii sulphuric acid, and for hydrogen sulphide use can be made of a neutral'solw tion of cadmium chloride.

The method herein described is claimed in ,my application, Serial No. 528,861, and therefore is not claimed herein.

it Will .be obvious to those skilled in the art to which the invention relates that modifieations'rmay be made not only7 in procedure butrlalso in construction and arrangement Without departing from the spirit of the in vention which is not limited as to those matters or otherwise than as the prior art and theappended claims may require.

It claim:

1. Apparatus for the quantitative deter -mination of constituents in illuminating gas comprising the combination of an electric balance having two of its arms provided with conductivity cells and havingv its bridge provided With abalance indicator and with` a balance adjuster including a. scale, inlet tubes having tunnels and communieating- With the lower parts of the cells respectively,

parts of the cells,4 rods adjustable endwise in respect tolboth of the electrodes With` which each cell isprovided, thermometers for the cells, meansfor connecting alternating current to they balance, said means including aswitch and a cabinet in which the parts are assembled to constitute a portable structure,.v substantially as described.

2. In apparatus of the class described the 10 combination of a pair o f conductiyity cells provided with fixed electrodes and means vvaccessible from the exterior of the cells and adapted to vary the capacity of,the cells,

whereby the constants adjusted to equality.

' WALTER'H. FULWEILER.

of the cells can be 

